I'm pretty new to this site, but I have a question that I know someone on here will help me with. My father has a 290 stihl, farm boss and was using it this weekend. OOPS, put the wrong fuel in it, not a mix. Small engine guy looked at it and said it is beyond repair because of the pistons. What do you guys think? The saw is only 2 years old, used maybe 5 times. Thanks.